When I unlock a new weapon there doesnt seem to be any way to see what the weapon actually looks like without first purchasing it and going out to use it to see if I like the visual. Every other costume piece you can check to see what it looks like w/o purchasing first. Just wondering if this was as intended or if there is a way to check it during editing your costume and I'm just not aware of it.

They're hoping to add in the ability to preview weapons at the Tailor in the future but its not in game now. Purchasing it and giving it a try is about the only way to test it at the moment.

One easy trick I use for a quick test is to attack one of the crates near the tailor a few times. Less legwork than running out into the field to find something to kill, and lets you make changes much quicker.

I also believe there are some posts around the forums with people who have been taking pictures of the various weapon unlocks so you can see them. Don't know where exactly but search should be able to pick something up.